LCM( 10, 8 ) = 40
The formula for finding LCM is
$$ \text{LCM} (a, b) = \frac{ a \cdot b }{ \text{GCD}(a,b)} $$In this example we have: a = 10, b = 8 and GCD(10, 8) = 2.
$$ \text{LCM} (10, 8) = \frac{ 10 \cdot 8 }{ \text{GCD}(10,8)} = \frac{ 80 }{ 2 } = 40 $$